package com.dzsw.javabase.str;

import java.util.Optional;

public class StringBuilderSample {

    public static void main(String[] args) {

        StringBuilder sb = new StringBuilder();
        sb.append("str").append("@")
                .append(Optional.ofNullable(null))
                .append("@");
        System.out.println(sb.toString());
    }
}
